Well, it's not normal. Air shouldn't leak out in just a couple of days (just on one side).
2 Peeps, you don't say what year your coach is but you may need new airbags or a valve is stuck or is failing. Generally, if an airbag coach is sitting for quite sometime, it will fall evenly.
Just for reference, our 2008 Monaco Dynasty that we ordered new and kept for 7.5 yrs. and 70,000 miles didn't leak or lean. We had hydraulic and air leveling.
MM.